Jeannette Walls’ 2005 memoir “The Glass Castle,” about coming to terms with growing up with her very unconventional parents, spent five years on the New York Times bestseller list. It has now been adapted for the screen by writer-director Destin Daniel Cretton (“Short Term 12”), and Walls visited Dallas recently to talk about the film.

“It was the most cathartic thing I’ve ever done,” Walls said of writing the book, which details her troubled but still loving relationship with her father Rex and mother Rose Mary, with whom she and her three siblings—two sisters, one older and one younger, and a brother—traversed much of the Southwest, moving from house to house, until they finally settled in Rex’s home town of Welch, West Virginia, living a hardscrabble life in primitive conditions while their mother obsessed over her painting and Rex battled alcoholism while writing poetry and dreaming big about constructing the utopian glass castle that gave the book its title.

The book was optioned for adaptation to the screen fairly early on, but actual work on the film stalled. Walls herself was asked whether she wanted to write the screenplay, but declined. “I didn’t want to do it,” she explained. “That’s not my medium, I don’t understand filmmaking.”

The job finally went to Cretton, and when Walls was asked whether she had seen his previous film “Short Term 12” she replied, “I did not until he was hired to do this. I rushed out and watched it, and I now call it the second-best movie ever made.”

Cretton and his co-writer Andrew Lanham made changes from the book, but they do not disturb Walls. “It was not at all frustrating,” she said. “I thought he did a spectacular job. He has a profound understanding [of the medium]. I was in awe of the way that he did take certain liberties with the story—he telescoped a few things, and expanded a few—but I understand why he did what he did for storytelling purposes.”

Walls was equally enthusiastic about Cretton’s direction. “He gets performances out of kids that are unbelievable. And adults as well. He brilliantly discerns who you are,…understands the pain and love and joy and despair” and then coaxes it from the actors.

“He started out as a film editor,” Walls explained, “and the actors often said they had never worked with someone who is so clear about what he wants out of a performance and out of a scene. Just spending time on the set watching him with the actors and the camera people, he was this calm force. It was like watching a Ferris wheel or something. There was always action going on around him, and with all these little boxes going on, he was this same constant, strong center. It was beautiful, and I know I couldn’t have done what he did.”

Though Walls visited the shoot on and off, there was one location—Welch—where she did not go. “Destin wanted to shoot it on location [in Welch],” she said, “because there would be huge mountains in the background, and he said they were majestic and gorgeous, but they also close you in, and he felt that once viewers saw that, they would understand so much about the place, like the sunlight a color that you’ve never seen before.”

But she added, “I did not visit while they were filming in West Virginia. There are very mixed feelings about me in my home town. I asked Destin, ‘Do you want me to go with you and show you around?’ and he said, ‘No, I’ll be fine,’ and…it was kind of magic—they ended up loving him. He’s just that kind of guy—he made friends and made things happen.” She recalled how he shot scenes at the local paper where she had once edited her school’s paper, and how he arranged a sequence at the football field where she had photographed the games. “The coach, she got cheerleaders to recreate seventies-era cheerleading costumes” for their routines, she enthused.

Walls also spent time with Brie Larson, who plays her in the film, but added that the actress really didn’t need to use her as a model. “I did [work with her], but she got it right away,” she said. “She’s really smart. She’s just a genius. She was always picking up on things that I did. I’m more than satisfied [with her performance]—I’m overjoyed.”

Watching the finished film, Walls said, was not the same as writing the book: “It was a different experience in that writing the book was in some ways a realization, like putting the pieces of the puzzle together—you don’t realize what was going on until you put it all down. It was a bit shocking to me. This was the experience of being fully understood by others…through the brilliant, empathetic actors and director and filmmakers who get it and fully understand.”

Asked whether her siblings had seen the picture, Walls said, “They have not. They don’t think they want to go see it at a screening in public. My mother saw the trailer and was just overjoyed by it–even though she’s depicted as a villain and our lives will be depicted as pathetic, the joy and exuberance come through. The minute that she saw Woody Harrelson, she said, ‘He looks just like Rex—and he acts just like Rex!’ And she saw Naomi Watts and said, ‘She looks just like me!’”

In a very real sense, Walls added, the film is a celebration of her father, who died of a heart attack in 1994. Rex Walls clearly had demons, arising to some extent from being abused as a child—the portrayal of his ferocious mother in the film is unforgettable. But Walls added that though his glass castle was never built, “I think dad’s dream did kind of come true, in that he…passed on his hopes and his dreams to his children. I think what this movie represents is the realization of his dream.” She pointed in particular to a song written for the film. “The lyrics were culled from dad’s poetry,” she noted.

And, Walls concluded, while much of the film, like the book, portrays the harshness of the family’s life together, “there are moments of hope and beauty and triumph, even in what looks like despair.”